1. Field of the Invention
The present invention relates to a data multiplexing apparatus for timeshare-multiplexing a plurality of variable rate data and a multiplexed data demultiplexing apparatus for demultiplexing multiplexed data into a plurality of original data.
2. Description of the Prior Art
So far, to timeshare-multiplex a plurality of variable rate time sequencing data (for example, compressed digital moving picture (or sound) data) and to store them on a data storing medium, a plurality of data generated in a particular time of period were grouped together (this grouped data is hereinafter referred to as a pack), a header was added at the beginning of the pack, a code representing a time was written in the header, and thereby, the multiplexed data was generated. To demultiplex the multiplexed data into the original data, the data transfer rate of the data storing medium was adjusted in accordance with the time written at the pack header.
In the above mentioned conventional data multiplexing method, since a plurality of data generated in a particular period of time was grouped together as a multiplexing unit, the data length of the multiplexing unit varied, so that when this multiplexed data was stored on the data storing medium, the multiplexing unit could not be matched with the storing unit of the data storing medium.